Example embodiments of the present inventive concepts relate to a distance calculation technology using a depth sensor (alternatively, a distance sensor), and more particularly to a method of distinguishing an ambiguity distance using a light signal having a special modulation pattern and demodulation signals input to each unit pixel, and/removing the ambiguity distance, and/or devices performing the method.
A sensor is an element which detects a state or a position of an object, and converts a result of the detection into an electrical signal. As a type of the sensor, for example, a photo sensor, a temperature sensor, a pressure sensor, a magnetic sensor, or a depth sensor may be used.
The depth sensor among these sensors may measure a delay time or delay phase taken until a pulse signal output from a light source is reflected and returned by an object, and calculate a depth or a distance between the depth sensor and the object. The pulse signal may be a microwave, a light wave or an ultrasonics wave. The depth sensor may calculate a depth or a distance using conventional methods, for example, a time of flight (TOF) method. The depth or the distance calculated by the conventional methods may create ambiguity (i.e., ambiguity distance) in a range of measurement. For example, objects at a certain range of measurement distance may have a same phase value for a certain modulation frequency.